He said: "Problem gambling is Britain's hidden epidemic and we must treat it as a public health emergency.

"Current gambling regulation is not up to the job of protecting addicts and those at risk of addiction.

"Treatment is patchy across the country and too often patients are misdiagnosed and not treated by specialists who can spot the signs of gambling addiction."

Mr Watson said gambling firms must take "more responsibility for harm caused by their products and contribute more to research and treatment".

He added: "The refusal of the current government to address any of these issues is letting problem gamblers and their families down."

Paddy Power and Betfair said they supported a reduction in pre-watershed advertising.

They said: "We are mindful that young children may be exposed to TV gambling advertising pre-watershed during live sport and increasingly aware of the growing social, media and political concern about this unintended exposure.

"For these reasons and to preserve the long-term value of our brands we are supportive of a reduction in the amount of pre-watershed advertising.

"Due to the fragmented and competitive nature of our sector, we believe any reduction must be policy-led as individual operators cannot act unilaterally."

The Conservative Party said Labour had liberalised the gambling market when they were in power and that it was now "correcting Labour's mistakes".

Chris Skidmore, the Tories' vice chairman for policy, said it had taken numerous measures, including: "Ensuring tighter rules on gambling advertising, increasing protections around online gambling, launching a multi-million pound awareness campaign, commissioning research on the harms of problem gambling, and slashing the maximum stake on fixed odds betting terminals..."